Guy
McPherson No
fireworks. He admitted his ignorance about climate change. But only
one-on-one, not publicly.It is quite something to admit the limits of one's knowledge in private and then, the next day to write an attack the next day.Prof. Renwick may have been involved in writing the latest IPCC reports but nothing he has said has forced me to alter my impression (confirmed above) that his knowledge is somewhat sketchy outside of his area of expertise, which is atmospherics although he seems to have got some aspects of that wrong.Unfortumately for many just having this "expert'" preaching steady-as-you-go will be enought persuade some people. The following is a brief discussion I had with Guy on Prof. Renwick's piece (below).I apologise for the quality of the recording.

Here is Dr. Renwick's piece on Guy

Guy
McPherson and the end of humanity (not)

Is
climate change going to wipe out humanity over the next 10 years?
Prof Jim Renwick doesn’t think so…

Ecologist Guy
McPherson has
been touring New Zealand for the past couple of weeks,
explaining why humanity has only 10 years to live (a kind-of Ziggy
message that
has immediate appeal to me). After hisappearance on
the Paul Henry breakfast show, I was called by TV3/Newshub for
comment. Based on my understanding of climate change science I said
that though the situation is very serious — dire even —
extinction in 10 years is not
going to happen.
When I gave my remarks to Newshub, I knew little about McPherson but
I understood that he is a very knowledgeable biologist who should not
be dismissed lightly.

So,
what’s the story? Is McPherson right? Is the IPCC woefully
conservative and keeping the truth from us all? I had the opportunity
to hear Prof McPherson speak in Paraparaumu on Saturday (Dec 10th) to
get more insight into what his views really are. It was a very
interesting presentation, and a very interesting discussion with the
audience of 50-odd Kāpiti coasters who showed up to hear him. As the
old saying goes, extraordinary claims require extraordinary evidence.
What we heard was extraordinary for sure, but was not too convincing
in terms of evidence.

McPherson’s presentation
was as much philosophy as science. Much of his message is built
around the undeniable truth that we are all, one day, going to die.

Hence, we would do well to live in and for the present, express our
love to those close to us, and act rightly according to our own
beliefs and principles. Excellent advice, and a great philosophy for
living well, what you would be told in any number of “life-coaching”
books. Where he differs from most is in saying that all of us, i.e.
all of humanity, and most other species, will be extinct in 10 years
or so. Why is that, you might ask?

The
detail on his view of the climate system can be gained by reading his
“monster
climate change essay”.
A briefer overview, and what he bases much of the scientific side of
his presentation on, comes from a
blog postat
the Arctic-News blogspot site, written by “Sam Carana” (not
his or her real name – you know why). This piece suggests that the
globe will warm around 10°C in the next decade, and since such
warming was associated with mass extinctions in past epochs, humanity
and most vertebrates etc will be toast very soon.

The
blog post starts by assuming the February 2016 global mean
temperature represents the current average temperature of the earth,
then throws in another 0.8°C for pre-1900 (0.3°C) and unavoidable
future (0.5°C) warming. This is pushing it, as February was the
warmest single month on record (in difference from normal terms),
several tenths of a degree above the annual mean for 2016, and the
amount of unavoidable future warming is small (maybe 0.1°C?), should
greenhouse gas emissions stop now.

However,
the next steps are where McPherson’s grasp of the science seems
shakiest. Cutting aerosol pollution to zero (as would happen when and
if industrial society falls over) will unmask another 2.5°C of
warming. This is a factor of ten too large, as the actual amount
would be around 0.25°C by current best
estimates (see figure
10.5). Reduced planetary reflectivity (albedo) from loss of Arctic
ice will add another 1.6°C (perhaps in the Arctic, but not in the
global mean), plus the water vapour feedback, seafloor methane
release etc will add an extra 3.5°C. So that’s another 7.5°C on
top of essentially where we are at now, giving a total of about 10°C
warming compared to pre-industrial, assumed to happen in the next 10
years. Then, all the world’s nuclear reactors melt down, and we are
all extinct.

The
way Guy McPherson talks about water vapour shows his sketchy grasp of
atmospheric physics. He states that most of the water vapour in the
atmosphere is above 6km altitude, where it “acts like a lens” to
heat the earth. Most of the water vapour is actually in the lowest
few kilometres of the atmosphere, as the upper troposphere is too
cold to support much water vapour. Perhaps he’s thinking of the
release of latent heat in the tropics, which does occur mostly in the
upper troposphere, leading to a warming “hot spot” in the
tropical upper troposphere as greenhouse gas concentrations rise (See
AR5 WG1,
figure 12.12).

Water
vapour is of course a critically important part of the climate change
story and is the main amplifying feedback of greenhouse gas increase.
McPherson is trained as an ecologist, so it’s no surprise that he
isn’t totally on top of the vertical profile of water vapour in the
atmosphere. But, if your public profile depends on your image as an
authority on “global warming”, you would do well to be clear on
the science.

Now,
the potential consequences of climate change, and the lurking
feedbacks such as Arctic methane release and other
carbon cycle changes,
are an extremely serious concern, one that I think the governments of
the world have yet to really take on board. The risks of severe food
and water shortages, population displacements and conflict over
resources, already has the potential to endanger hundreds of millions
of lives – even with another degree or two of warming (as outlined
in the last
IPCC report).
But truly catastrophic and extremely rapid climate changes do not
look to be on the cards, at all. Earth’s climate is not poised
for “runaway” change (as
per Venus),
nor is there any clear indication from the geological record that the
climate system is so sensitive to greenhouse gas increase that 10°C
of warming in 10 years is imminent, or even possible. The climate
community of course does not know everything about past climate
change nor about what the climate system is capable of if pushed
hard. But, the extinction in 10 years scenario is really at the outer
edge of speculation about the future.

Even
without imminent extinction, the consequences of climate change are
more than dire enough to galvanise us into action. My perception is
that concerted global action within the next decade can avoid the
worst consequences. The flip side is that business as usual, even for
another ten years, could lock in changes that do indeed put global
society at risk and threaten possibly hundreds of millions to
billions of lives. Not instant death but a very unpleasant future for
a very long time. I find that prospect plenty scary enough, and it
leaves room for us to take action. Let’s take it.

Gareth
adds: McPherson’s
views are a good example of real climate “alarmism”. Deniers
love to paint the IPCC or consensus position on climate change
as alarmist, thereby implying that their rejection of that consensus
is somehow sensible or moderate. McPherson’s stance shows that to
be a mere debating trick. The truth, of course, is that by rejecting
the consensus view on what we can expect, deniers are as extreme as
McPherson — polar opposites, but just as guilty of
exaggeration

Author:
James Renwick

I
am a climate researcher with a background in atmospheric dynamics and
statistics. I was involved in writing the 4th and 5th Assessment
Reports for the IPCC and am also on the joint scientific committee of
the World Climate Research Programme (WCRP)

I am not personally in a position to debate with the esteemed professor but after reading his comments about water vapor in the upper troposphere I suspect he might find himself in conflict with the following.

A
new study from scientists at the University of Miami Rosenstiel
School of Marine and Atmospheric Science and colleagues confirms
rising levels of water vapor in the upper troposphere – a key
amplifier of global warming – will intensify climate change impacts
over the next decades. The new study is the first to show that
increased water vapor concentrations in the atmosphere are a direct
result of human activities.

"The
study is the first to confirm that human activities have increased
water vapor in the upper troposphere," said Brian Soden,
professor of atmospheric sciences at the UM Rosenstiel School and
co-author of the study.He will also find himself in conflict with his colleague, emeritus professor Peter Barrett who, back in 2004, was forced to recant his contention that global warming will result in extinction because of the objections of people like Renwick.

The
winner of one of New Zealand's top science medals, Professor Peter
Barrett, has backed off a controversial claim that humanity faces
extinction within 100 years because of global warming.

Dr
Barrett, who was presented with the Royal Society's Marsden Medal in
Christchurch last night, gave the Christchurch Press notes for his
acceptance speech in which he planned to say: "If we continue
our present growth path we are facing extinction - not in millions of
years, or even millennia, but by the end of this century."

After
a storm of criticism, he changed the word "extinction" in
his speech last night to "the end of civilisation as we know
it".

Here is an earlier piece about James Renwick with a video which illustrates his views.

Perfect timing. Here is a video that came out today on global dimming, nuclear power stations, methane etc.The steady-as-you go approach of Prof Renwick is nonsensical and the IPCC computer modelling he is evidently wedded to has been shown to be completely inaccurate by actual observations.

2 comments:

In this post you said "He will also find himself in conflict with his colleague, emeritus professor Peter Barrett who, back in 2004, was forced to recant his contention that global warming will result in extinction because of the objections of people like Renwick." This is not true. You've made up this story. Do you make a pratice of this? The "extinction" statement was in the first draft of my short speech and sent to a Christchurch reporter that I trusted under a 24 hour embargo the day before the Royal Society's award ceremony. On further reflection I changed the text to "the end of civilisation as we know it" and that was in the speech I gave on the night. Sadly the reporter sent it through for publication the night I sent it and it had gone to press by the time I sent him the updated version. So no coercion by anyone....Em Prof Peter Barrett 10 April 2017

I apologise if I have misconstrued what happened in 2004. I did not, however "make this up". Here is the source (not mine)http://www.nzherald.co.nz/climate-change/news/article.cfm?c_id=26&objectid=3611421